Diseases of the lacrimal drainage system

We will refer to lacrimal system pathologies involving the outflow pathways, as well as to the recent advances in the management of canalicular and lacrimonasal duct anomalies, including modifications to dacrycystorhinostomy technique, treatment for congenital obstructions, and lacrimal intubations. Special emphasis will be placed on the usefulness of nasal and canalicular endoscopy for the examination and treatment of congenital obstructions and endonasal pathologies, as an aid for intubations and lacrimal surgery, as well as on reasons for failed procedures.     

Ocular biometry theory and practice

The paper presents elements of eye biometry theory and practice as seen by a young resident, in his first years of practice as ophthalmologist. The paper refers to the current stage of IOL measurement technique. Also, challenges for the younger generation are presented, such as new formulas for the patients who have undergone refractive surgery, measurement solutions for the patients affected by cataract, whose vitreous was replaced by silicone, and last but not least, the proper approach as regards biometrical measurements for children.     

Iris claw lens

The iris claw lens does not have some of the disadvantages of lenses fixed in the anterior chamber angle. It is clipped to the iris from the front and does not touch the structures of the angle. It is useful as a stand-by lens and for secondary implantations, as well as for certain other indications, such as a traumatized eye with anterior synechiae. It is conceivable that in the future this lens type may gain in importance as a carrier of a concave optic for use in myopic eyes.     

Bivectorial transparent stimuli simultaneously adapt mechanisms at different levels of the motion pathway

The motion aftereffect (MAE) to drifting bivectorial stimuli, such as plaids, is usually univectorial and in a direction opposite to the pattern direction of the plaid. This is true for plaids that are perceived as coherent, but also for other plaids which are seen as transparent for most or all of the adaptation period. The underlying mechanisms of this MAE are still not well understood. In order to assess these mechanisms further, we measured static and dynamic MAEs and their interocular transfer (IOT). Adaptation stimuli were plaids with small (coherent) and large (transparent) angles between the directions of the component gratings and a horizontal grating, which were adjusted in spatial frequency and drift velocity so that the pattern speed and vertical periodicity remained constant. Test stimuli were horizontal static or counterphasing gratings with the same periodicity as the adaptation stimuli. MAE duration was measured for monocular, binocular and IOT conditions. All static MAEs were smallest for the transparent plaid and largest for the grating, while all dynamic MAEs were constant across adaptation stimuli. IOT was twice as big for dynamic MAEs as for static MAEs, and did not vary with the adaptation stimuli. Other adaptation stimuli were plaids that differed in intersection luminance, contrast or spatial frequency, resulting in different amounts of perceived coherence. MAEs and IOT did not vary with perceived coherence. The results suggest that the MAE for bivectorial stimuli consists of low-level adaptation (dependent on local component properties, small IOT), as well as high-level adaptation (dependent on global integrated pattern properties, large IOT), which can be measured independently with static and dynamic test stimuli.     

The zebrafish as a model organism for eye development

In recent years, the zebrafish has become a favourite model organism for biologists studying developmental processes in vertebrates. Its rapid embryonic development, the transparency of its embryos, the large number of offspring together with several other advantages make it ideal for discovering and understanding the genes that regulate embryonic development as well as the physiology of the adult organism. Zebrafish are very visually orientated, and their retina and lens show much the same morphology as other vertebrates including humans. For this reason, they are well suited for examining ocular development, function and disease. This review describes the advantages of the zebrafish as a model organism as well as giving an overview of eye development in this species. It has a particular focus on morphological as well as molecular aspects of the development of the lens.     

Corneal biomechanics: a review

Biomechanics is often defined as ‘mechanics applied to biology’. Due to the variety and complexity of the behaviour of biological structures and materials, biomechanics is better defined as the development, extension and application of mechanics for a better understanding of physiology and physiopathology and consequently for a better diagnosis and treatment of disease and injury. Different methods for the characterisation of corneal biomechanics are reviewed in detail, including those that are currently commercially available (Ocular Response Analyzer and CorVis ST). The clinical applicability of the parameters provided by these devices are discussed, especially in the fields of glaucoma, detection of ectatic disorders and orthokeratology. Likewise, other methods are also reviewed, such as Brillouin microscopy or dynamic optical coherence tomography and others with potential application to clinical practice but not validated for in vivo measurements, such as ultrasonic elastography. Advantages and disadvantages of all these techniques are described. Finally, the concept of biomechanical modelling is revised as well as the requirements for developing biomechanical models, with special emphasis on finite element modelling.     

远程医疗用于早产儿视网膜病变防治的意义

早产儿视网膜病变（ROP）是目前世界范围内儿童致盲的主要原因之一,虽然防治策略已取得了很大进步,但其管理体系方面尚存在许多限制.作为一种新兴技术,远程医疗对于提高ROP防治效率和管理质量具有较大潜力,但同时也面临着许多挑战.本综述对远程医疗用于ROP防治的必要性、可行性、优势及目前尚存在的问题进行了总结,特别强调了远程医疗用于ROP防治具有准确性高、可靠性高、效率高、性价比高的优势,具有广泛应用的前景.     

重视角膜胶原交联术在眼科的临床应用和研究

角膜胶原交联术经过十余年发展,在欧洲已成为治疗膨隆性角膜病变的常规手段,可以有效地阻止角膜膨隆的进展,同时在眼科临床其他方面也有很好的应用前景。目前该技术仍在国家审批过程中,我国作为角膜植片严重匮乏、广泛大量开展角膜屈光手术、严重感染性角膜炎仍是主要致盲因素之一的国家,我们亟需重视对角膜胶原交联术的认识,倡导并推动该技术在我国眼科的研究和临床应用。     

Changing indications for enucleation and selected unusual pathologies

PurposeTo survey clinical indications for enucleations received within a single specialist ophthalmic pathology department over a 21-year period.MethodsCases were identified from the departmental records and categorised by indication type as well as by year.ResultsOver time, there has been a decreasing trend in eyes removed for end-stage indications such as phthisis, blindness or pain, as well as a decrease in eyes removed following trauma.ConclusionWith the reducing number of eyes removed for end-stage disease and trauma, the majority of enucleations performed are now for malignancy. However, eyes are still removed for other indications. A selection of rarer pathologies is presented.     

To the definition of the reduction of ability in the law of incometax (author's transl)]

Out of jurisdiction and commentaries by the Federal minister of finance and the minister of labour and social affairs it is proved, that the characteristic of externally recognizable, permanent loss of bodily mobility is existent not only for one-eyedness but as well as for reduction of visual acuity, provided (reduction of ability) of 25% or more is present. This statement is good for reductions of Personal income tax as well as Wage tax. The estimation of the degree of disability is to be made according to "leads on the medical expertise on the state provision for the deserving", Edition 1973.     

Iris lymphoma—a systematic guide for diagnosis and treatment

Iris lymphomas are rare malignant neoplasms arising either as primary tumors in the iris or as secondary tumors involving the iris. We summarize previously published data and make recommendations for work-up strategies for cases of suspected iris lymphoma. Our objective is to provide a structured overview of the typical clinical symptoms and signs, the pathologic, ophthalmic, as well as hematologic work-up for diagnosis, treatment, and follow-up of iris lymphomas and offer a flowchart on how to diagnose and treat these tumors.     

Pharmacological therapy for age-related macular degeneration. Current developments and perspectives

Current therapeutic options for age-related macular degeneration are very limited and are, at best, only capable of slowing visual loss. Because of this an intensive search for prophylactic agents capable of inhibiting the progression of this disease from early into late forms, as well as for new therapeutic approaches has been undertaken. While neuroprotective substances are hoped to prevent cellular death in this disease process, multiple substances capable of inhibiting neovascularization, such as VEGF inhibitors, are in clinical trials. Inhibitors of matrix-metalloproteinases (MMP) and chemotherapeutic agents are also being clinically tested as novel therapies for AMD. Other targets include the inhibition of toxic compound formation in lipofuscin granules such as AZ-E.What follows is an overview of different substances and their stages of development in clinical trials.     

Smartphones in ophthalmology

The potential usefulness of smartphones in the medical field is evolving everyday. This article describes various tools available on smartphones, largely focusing on the iPhone, for the examination of an ophthalmic patient, for patient and physician education, as well as reference tools for both ophthalmologists and vision researchers. Furthermore, the present article discusses how smartphones can be used for ophthalmic photography and image management, and foremost, the usefulness of the applications such as the Eye Handbook for the ophthalmologist and interested students, patients, physicians, and researchers, currently available in the iPhone.     

Cleaning hydrophilic contact lenses: an overview.

The composition of the major, critical component of the amorphous deposits forming on hydrophilic lenses during wear was identified and reported by Karageozian as basically proteinaceous in nature. The research surrounding the identification has produced animal and laboratory models for testing the parameteres involved in the protein deposition, as well as in its removal. A standardized system for classifying the protein deposits during and after formation, along with the experimental animal and laboratory models allows a relatively complete development of the predictive tests required for a compound or a product intended for use as a cleaner of hydrophilic lenses. These predictive tests have been run on several available cleaning systems as well as on a new one; the results indicate clearly that, unlike the available systems, the new system will safely remove deposits from hydrophilic lenses. The laboratory predictive test results have been borne out by clinical trial; the clinical results indicate the suitability of the new formulation and the predictive capability of the test models developed.     

Reliability and significance of measurements of a-wave latency in rats

PURPOSE: To determine whether measurements of the a-wave latency of the electroretinogram (ERG) can be made as reliably as that of the implicit time (IT) in rats. In addition, to determine the relationship between the potential level selected for the latency and the baseline potential level. METHODS: ERGs, elicited by different stimulus intensities, were recorded from Long-Evans rats. The a-wave latency was determined by measuring the time between the stimulus onset and the beginning of the negative-going a-wave, and the IT was measured as the time between the stimulus onset and the peak of the a-wave. To test the reliability of the measurements of the latency, the a-wave latency and the IT were measured by three independent observers for the same 15 ERGs. RESULTS: The mean a-wave latency was approximately 14 milliseconds, and the mean a-wave implicit time was approximately 36 milliseconds. The mean of the a-wave latency and the IT, as measured by the three observers, were within 1 millisecond of each other. The coefficient of variation was as good for the latency as for the IT of the a-wave. The potential level selected for the latency was lower than the mean baseline potential level by 1 to 2 standard deviations. CONCLUSIONS: Selection of the a-wave latencies can be made as reliably as that for the IT. Because the a-wave latency is not affected by the activity of the second order neurons, the latency is a better measure than the IT of the time course of the a-wave.     

Neuhann capsulorhexis: a technic for reliable implantation of the capsule sack

The Neuhann Capsulorhexis allows for a continuous, circular opening in the anterior lens capsule. After excavation of the lens matter the circular round edge in the anterior capsule provides maximum stability in the zonulolenticular diaphragm and facilitates controlled in-the-bag implantation of the lens haptic. Histologic studies of cadaver eyes have revealed that the correlation between the position of the lens loops as intended by the surgeon intraoperatively and their actual positioning is poor. It has therefore not been possible to prove the advantages of all-in-the-bag implantation as compared to sulcus fixation. The Neuhann Capsulorhexis reduces the morphological variability of the anterior capsule; furthermore, the position of the lens haptic can easily be determined both intraoperatively as well as postoperatively. This is a prerequisite for evaluating the best position for the lens haptic as well as for clinical evaluation of new types of intraocular lens.     

Basic principles and clinical application of retinal laser therapy

The scientific background of laser photocoagulation of the ocular fundus was studied extensively by several investigators in the 1970 s and 1980 s. The basic principles were successfully resolved during that time and clinical consequences for proper application of the laser photocoagulation for various diseases were deduced. The present paper gives an overview about the physical basics of laser-tissue interactions during and after retinal laser treatment and the particular laser strategies in the treatment of different retinal diseases. Thus, it addresses the issue of the impact on tissue of laser parameters as wavelength, spot size, pulse duration and laser power. Additionally, the different biological tissue reactions after laser treatment are presented, such as, e. g., for retinopexia or macular treatments as well as for diabetic retinopathies. Specific laser strategies such as the selective laser treatment of the RPE (SRT) or the transpupillary thermotherapy (TTT) are presented and discussed.     

Chitosan as tear substitute: a wetting agent endowed with antimicrobial efficacy.

A cationic biopolymer, chitosan, is proposed for use in artificial tear formulations. It is endowed with good wetting properties as well as an antibacterial effect that are desirable in cases of dry eye, which is often complicated by secondary infections. Solutions containing 0.5% w/v of a low molecular weight (M(w)) chitosan (160 kDa) were assessed for antibacterial efficacy against E. coli and S. aureus by using the usual broth-dilution technique. The in vitro evaluation showed that concentrations of chitosan as low as 0.0375% still exert a bacteriostatic effect against E. coli. Minimal inhibitory concentration (MIC) values of chitosan were calculated to be as low as 0.375 mg/ml for E. coli and 0.15 mg/ml for S. aureus. Gamma scintigraphic studies demonstrated that chitosan formulations remain on the precorneal surface as long as commonly used commercial artificial tears (Protagent collyrium and Protagent-SE unit-dose) having a 5-fold higher viscosity.     

Vaccination for stab and bite injuries in the facial region

In cases of stab and bite injuries to the face there is a risk of general infection and the necessity for an active and/or passive immunization must be considered by the first treating physician. In Central Europe tetanus, rabies, hepatitis B and C as well as HIV must be taken into account as possible consequences of such injuries. With regard to a tetanus immunization the indication for the post-exposition prophylaxis (PEP) should generally be as wide as possible. For other protective vaccinations a differentiated decision in co-operation with other fields of activity and public health authorities should be realized. The current recommendations for the systemic infections relevant in Central Europe are described.     

Acquisition of visual shape primitives

Shape primitives have long been proposed as components for object models in the visual system, and account for a considerable body of behavioral findings. While a large amount of effort has been devoted to the study of detection of these parts in the scenes, no research has been undertaken simulating the acquisition of these representations. We present a model which suggests how the shape primitives may be learned by experience in a self-organized fashion. This model offers the first successful unsupervised learning of shape primitives which are as complex as object parts and can serve as intermediate representations for various objects. The algorithm uses synthetic gray-level objects, each composed of several parts (primitives or else), and shape primitives emerge as a result of partial matches between several objects. Our algorithm does not use any a priori knowledge about any attributes of the patterns to be learned; and the recurrence of these visual patterns in various objects is the only basis for their emergence as new features.